Bo Xilai said his wife, who is serving a suspended death sentence for the murder of Neil Heywood, 'lies all the time'. Photograph: AFP/Getty Images

The disgraced Chinese politician Bo Xilai has continued his defiant performance on the second day of his trial, calling testimony by his former second-in-command "nonsense" and discrediting his wife's testimony as "fabricated".

Bo, 64, is standing trial in Jinan, the capital of coastal Shandong province, on charges of bribery, embezzlement and abuse of power. Bo, once considered a contender for some of China's most powerful political posts, has surprised observers by flatly denying some of the trial's central charges: that he received bribes from two powerful businessmen in the north-eastern metropolis of Dalian, where he was mayor in the 1990s.

On Friday, the court showed an 11-minute video testimony by Bo's wife, Gu Kailai, looking calm and composed in a black-and-white striped blouse. She said Bo was aware that one of the businessmen, Xu Ming, had given gifts to her and their son, 25-year-old Bo Guagua, including airline tickets, a Segway and expensive seafood.

Gu is currently in prison serving a suspended death sentence for the murder of the British businessman Neil Heywood – the root of her husband's downfall. Bo stands accused of interfering with the investigation.

Prosecutors allege that Bo received 21.8m yuan (£2.3m) in cash and gifts from Xu between 2000 and 2012. On Thursday, Bo denied the charges and, in a scathing cross-examination, forced Xu to admit that he was unaware of the gifts.

In the video shown on Friday, which was filmed on 10 August, Gu contradicted Bo's assertions and called Xu an old family friend. "We felt he was an honest person, well-mannered. He didn't have the airs of a businessman," she said.

Bo said his wife was "crazy", "lies all the time" and fabricated her statement under duress, according to court transcripts published online. He added that Gu would often compare herself to Jing Ke, a famous Chinese assassin who lived in the second century BC.

"Kailai used to say that when she killed Neil, she felt the same pride that Jing Ke felt when he went to assassinate the king of Qin," he said. "That's enough to prove she's not psychologically normal."

Bo's career imploded last year when his second-in-command, the police chief of Chongqing municipality Wang Lijun, fled to a US consulate in south-west China carrying stacks of incriminating documents. Gu's killing of Heywood was revealed in the ensuing fallout.

On Friday afternoon, the court also published testimony by Wang that shed light on the soured real-estate deal that led to Heywood's murder. Bo called the testimony "nonsense".